Wellhead connector



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INVENTOR:

WILLIAM J. HAYES HIS AGENT United States Patent 3,215,454 WELLHEAD CONNECTOR William J. Hayes, Torrance, Califi, assignor to Slieil Oil Company, New York, N.Y., a corporation of Delaware Filed Oct. 5, 1964, Ser. No. 401,483 2 Claims. (Cl. 28523) This invention relates to apparatus for use in drilling, completing and working over operations in oil and gas wells at offshore locations, and pertains more particularly to apparatus to be used with a marine conductor pipe which is a large-diameter pipe used to provide full-flow fluid communication between a vessel at the surface of a body of water and a wellhead assembly positioned on the ocean floor or at a substantial depth below the surface of the water.

In an attempt to locate new oil fields, an increasing amount of well drilling has been conducted at offshore locations, such for example, as off the coast of Louisiana, Texas and California. As a general rule, the strings of casing in a well, together with the tubing string or strings, extend to a point above the surface of the water where they are closed in a conventional manner that is used on land wells, with a conventional wellhead assembly being attached to the top of the casing. Recently, methods and apparatus have been developed for drilling and completing wells wherein both the well casinghead, and subsequently the wellhead assembly and the casing closure device, are located underwater at a depth suflicient to allow ships to pass over them. Preferably, the casinghead and wellhead closure assemblies are located close to the ocean floor. In order to install well-drilling equipment underwater at depths greater than the shallow depth at which a diver can easily operate, it has been necessary to design entirely new equipment for this purpose. Thus, when drilling and completing an oil well or a gas well at an offshore location, the wellhead connector of the present invention may be employed to secure the lower end of a marine conductor pipe to the upper end of a wellhead drilling assembly positioned on the ocean floor.

Wells drilled in deep water are generally drilled from vessels of varying design commonly known as drilling barges, vessels or platforms. Deep water wells are generally drilled by one of two methods. In one method a string of drill pipe extends downwardly from the drilling vessel to the drilling wellhead assembly, on the ocean floor, which is closed at the top by a circulation head with a flexible hose running from the circulation head back to the surface and to the drilling vessel so that drilling fluid may be circulated down the drill pipe, through the drill bit, and thence upwardly along the outside of the drill pipe, out the circulation head and up the flexible hose to the vessel again. In a second method, a large-diameter pipe known as a marine conductor pipe is put together and arranged to extend from the drilling wellhead assembly near the ocean floor to the vessel on the surface of the water. In the latter method, the drill pipe rotates within the conductor pipe with drilling fluid being circulated down through the drill pipe, through the bit at the bottom thereof, up the outside of the drill pipe within the well and thence upwardly through the annular space between the conductor pipe and the drill pipe, returning to the barge in the conventional way. The present invention is concerned with apparatus to be used in the second method described hereinabove.

One of the problems in drilling under-water wells from floating vessels is that of providing suitable connector means for securing the lower end of a marine conductor pipe to the top of a wellhead or a drilling wellhead assembly in a fluidtight manner. Heretofore, wellhead connectors of the type shown in US. Patent 2,962,096 to 3,215,454 Patented Nov. 2, 1965 Knox have been employed in drilling wellhead assemblies to secure a blowout preventer to a well casinghead and to secure the lower end of a marine conductor pipe to the uppermost tubular member of a drilling wellhead assembly, such for example, as to a mandrel connected to the Wellhead assembly co-axially with and above the blowout preventers. Connectors of this type employ a hydraulically-actuated piston which operates latches carried by the connector unit to drive them into recesses arranged on a mating member adapted to telescopically engage the connector. The pressure lines which actuate the piston of this type extend to the vessel at the surface. The arrangement of the operating piston is such that the latches of the connector are positively locked in position until actuating pressure fluid can be supplied to the other side of the piston. It has been found that drilling in certain locations, for example in Alaskan waters, the pressure fluid lines running from the vessel to the certain wellhead components may become clogged or damaged in some manner during the several weeks or months of operation necessary to drill the well.

In the event of a violent storm coming up during offshore well drilling operations, it is often desirable to withdraw the marine conductor pipe and drill string out of the well and back to the vessel so that they are not damaged in the event that the storm moves the drilling vessel of its anchored location above the well. This operation must be carried out as rapidly as possible for reasons of safety. Thus, if the pressure-fluid operating line to the wellhead connector at the bottom of the marine conductor pipe is plugged or damaged so that pressure fluid cannot be applied to unlock the connector from the wellhead drilling assembly, an extremely dangerous situation would arise with possibly the loss of considerable equipment including the entire marine conductor pipe.

It is therefore a primary object of the present invention to provide apparatus for connecting the lower end of a marine conductor to an underwater wellhead assembly while actuating the apparatus from a remote location.

It is another object of the present invention to provide a wellhead connector component adapted to be fixedly secured to the lower end of a marine conductor pipe and releasably secured to a mating wellhead component so that after the connected apparatus or components are lowered from the vessel at the surface of the water to the well at the ocean floor, the connector may be remotely actuated so as to become positively unlatched from the wellhead assembly on the ocean floor.

A further object of the present invention is to provide apparatus for releasably securing the lower end of a marine conductor pipe to the upper end of a wellhead assembly on the ocean floor in a fiuidtight manner without positively locking the marine conductor pipe to the wellhead assembly so that it could not be pulled olf in the event of an emergency.

Still another object of the present invention is to provide a wellhead connector device and sealing apparatus at the bottom of a marine conductor pipe for sealing the marine conductor pipe to an underwater wellhead in a manner such that a predetermined upwardly pull on the marine conductor pipe and the wellhead connector will separate it from the underwater wellhead assembly.

A further object of the present invention is to provide a wellhead connector for use at the lower end of a marine conductor pipe, said wellhead connector being adapted to be simultaneously sealed to and unlatched from an underwater wellhead assembly.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

varying from about 100 to 1500 feet or more.

FIGURE 1 is a diagrammatic view taken in longitudinal projection illustrating a floating drilling vessel positioned at the surface of the ocean with an underwater wellhead assembly positioned on the ocean floor;

FIGURE 2 is a longitudinal view taken in enlarged detail and partially in cross section of the wellhead connector of the present invention; and,

FIGURE 3 is an enlarged detailed view taken in cross section of one form of positive locking device carried by the latch operator for maintaining the latches in a retracted position during drilling operations.

Referring to FIGURE 1 of the drawing, a drilling vessel, barge or platform is generally represented by numeral 11. The drilling vessel is of any suitable type preferably, as illustrated, floating on the surface of a body of water 12 and being substantially fixedly positioned over a preselected drilling location by suitable vessel-positioning means or by being anchored to the ocean floor 13 by suitable anchors (not shown) connected to the anchor lines 14 and 15. Equipment of this type may be used when carrying on well drilling operations in water depths The drilling vessel is equipped with a suitable derrick 16 as well as other auxiliary equipment needed during the drilling of a well, such as a hoist system 17, rotary table 18, etc. The derrick 16 may be positioned over a drilling slot or well which extends vertically through the vessel in a conventional manner. When using the equipment of the present invention, the slot of the vessel may be centrally located or extend in from one edge. However, drilling operations may be carried out over the side of the vessel without the use of a slot, as from a portion of the deck of the vessel which is cantilevered out over one end. Additionally, it is to be understood that the equipment of the present invention may also be used when drilling a well from any suitable operational base positioned above the surface of the water, such for example, as from a drilling barge having legs extending from the ocean floor, or from a platform permanently positioned on the ocean floor.

A typical underwater wellhead structure is illustrated in FIGURE 1 as comprising a base member 21 which is positioned on the ocean floor 13 and is fixedly secured to a conductor pipe or large-diameter well casing 22 by means of a ball-and-socket joint 23. During drilling operations a drilling wellhead assembly is removably secured to the top of a foundation pile 24 which in turn is secured to the top of the ball-and-socket joint 23. In the wellhead structure illustrated, the drilling wellhead assembly is secured to the top of a casinghead 25 which in turn is mounted at the top of the foundation pile 24. The combined casing 22, foundation pile 24 and casinghead 25 form a continuous tubular member or pipe extending up from the ocean floor through which drilling operations are conducted.

The drilling wellhead assembly illustrated includes a detachable wellhead connector or drilling bonnet 27 of any suitable type well known to the art. Fixedly secured above the wellhead connector 27 is a ram-type blowout preventer unit 28, a bag-type blowout preventer unit 29, a flexible joint 30, a remotely-operable quick-disconnect coupling and sealing apparatus 31, and a sectionalized marine conductor pipe assembly 32 extending to the vessel 11 at the surface 12. The remotely-operable quickdisconnect coupling and sealing apparatus 31 will be designated hereinbelow as a wellhead connector. Passing down alongside the wellhead connector 31 (FIGURE 1) are a pair of smaller-diameter auxiliary pipes 39 and 40 which may be readily disconnected by any suitable type of pull out connector at points 41 and 42.

Referring to FIGURE 2 of the drawing, the lowermost section of the marine conductor pipe 31 is shown as being provided with a female section 42 of a coupling adapted to stab over a cooperating male section 43 of the coupling which is bolted to the top of the Wellhead connector 31. The male section 43 of the stab-type coupling is provided with conical recesses 44 for receiving locking bolts 45 carried by the female section of the coupling. It is apparent that the bolts 44 are of a form that may be turned by a diver with a wrench or by an underwater robot.

In FIGURE 2 of the drawing, the wellhead connector 31 is illustrated as comprising a body member 31a having a vertical axial throughbore of a size sutficient to receive therein an upwardly-extending tubular mandrel or projecting well member 91 which is fixedly secured to the upper end of the flexible joint 30 in the marine conductor pipe assembly. It is to be understood that the mandrel 91 may be bolted at its lower end to the upper end of the flexible joint 39 or alternatively to any other component of the drilling wellhead assembly. For ease of illustration the connecting bolts have been omitted. The outer surface of the mandrel 51 is provided with a latching groove or a series of latching grooves 52 adapted to receive the latching members 53 of the several latches 49 carried by the coupling housing 31. One form of a suitable latch is shown in FIGURE 2 as being spring actuated by a compression spring 54 which urges the latch 53 laterally at all times and inwardlytoward the center of the wellhead connector 31. A pressure fluid conduit or hydraulic line 55 is provided whereby a hydraulic fluid may be pumped into the latch device 49 to act against a piston 56 carried therein to move the latch member 53 out of the groove 52 to an inoperative position. Suitable retractable locking dogs 57 are carried on the shaft 58 (FIGURE 3) and arranged to move radially outwardly by the compression spring 54 and prevent the latch member 53 from being reengaged in the groove 52. Thus, once the latch member 53 has been disengaged from the groove 52 it cannot re-engage the groove 52 until the apparatus has been returned to the vessel and re-set in the latching position. To re-set the locking dogs 57 so that the latch 53 may move to its operative position, a removable cap 60 is removed and the locking dogs 57 are com:

pressed against springs 61 into recesses 62 within the shaft 58.

The inner wall of the body member 31a is also preferably provided with a seating shoulder 64 adapted to be received on a cooperating sea-ting surface 65 carried on the outer surface of the mandrel 51. Alternatively, the upper end 66 of the mandrel 51 may receive a recessed landing surface 67. Additionally, the outer surface of the mandrel 51 is preferably provided with a series of grooves 68 into which an expandible hydraulically-actuatable annular sealing member 71 may be expanded. While the annular sealing member 71 may be carried on the inner wall of the bore of the body member 31a, it is preferably carried within a recess in the body member which forms a chamber 72 in which hydraulic fluid can be injected, as through conduit 73, to force the sealing member radially inwardly compressing it in a fluidtight manner around the mandrel 51. The hydraulic conduits or pressure lines 55 and 73 are preferably inter-connected to a common manifold pressure line 74. Thus, as hydraulic pressure fluid is applied to manifold line 74 from a control panel on the vessel 11 on the surface of the water 12, the annular sealing member 71 is expanded inwardly and contracts around the grooved section of the mandrel 51 to form a fluidtight seal therearound and to provide a predetermined pull out resistance of say 5,000 pounds, that is, the force that is necesary to lift the wellhead connector housing 31 off the mandrel 51 while the seal 71 is still being actuated thereagainst. Simultaneously with the actuation of the seal member 71 against the mandrel 51, the latches 49 are energized so that their latch members 53 are retracted from the latching groove 52. If desired, individual actuating hydraulic pressure lines may be used to the chamber 72 and the latches 49, respectively.

Drilling operations may be carried out in an under water well with the wellhead connector apparatus 31 arranged in the described manner, that is, with the sealing member 71 activated and the latches 49 retracted so that in an emergency the marine conductor pipe assembly 32 (FIGURE 1) can be readily pulled ofi the mandrel 51 at the top of the drilling wellhead assembly even though the hydraulic pressure lines 55, 73 or 74 are plugged so that the seal cannot be de-activated. By employing a wellhead connector of this design, there is no danger of the latches 53 sticking or freezing in the latching groove 52 for any of several reasons. In the event that a well is being drilled for several weeks, say in Alaskan waters, there is always a possibil ty of the hydraulic lines 55, 73 or 74 becoming plugged, frozen or damaged so that the latch members 53 could not be retracted if the locking dogs 57 were not provided on the stem 58 of the latch 53 to hold the latch in its inactive position, as illustrated.

When the equipment illustrated in FIGURE 1 is originally run down to the wellhead, the components 25, 27, 28, 29 and 30, together with mandrel 51 (FIGURE 2), may all be connected together and hung from the latches 53 which at that time, during the lowering operation, engage annular groove 52 in a locking position. It is only after the equipment has been all lowered and seated at its wellhead position that pressure fluid is pumped down the hydraulic manifold line 74 from the vessel to seal the wellhead connector about the mandel 51 and to retract the latches 53 from the groove 52.

I claim as my invention: 1. A wellhead connector assembly comprising a body member having a passage extending axially therethrough, said body member being positionable in telescopic relation with vertical wall means of a longitudinally projecting well member having an axial passage therethrough forming an unimpeded throughbore passing through said body member and said well member, cooperating connector means carried by the adjacent walls of said body member and said well member,

one portion of said connector means comprising shoulder means formed by a recessed area in the outer wall of said well member,

the other portion of said connector means comprising shoulder-engaging latch means carried by said body member in the adjacent wall thereof in a position for registering with said shoulder means, said latch means being substantially laterally movable into and out of engaging relation with said shoulder means,

compression spring means carried by said body member in operative engagement with said latch means for normally urging said latch means inwardly at all times into engagement with said shoulder means, fluid operator means for said latch means carried by said body member and operatively connected to said latch means for urging said latch means to a retracted position out of engagement with said shoulder means.

latch locking means carried by said body member adapted to lock said latch means in a retracted position,

a resilient annular seal member on the inner wall of said body member formed by the axial passage therethrough, said seal member being radially inwardly contractible about a well member when it is positioned in said axial passage,

chamber means formed in said body member around the outside of said annular seal member, said chamber means adapted to be connected to a source of fluid pressure,

weight-supporting shoulder means formed on the inner wall forming the passage through said body member for seating on said Well member when in engagement therewith, and

a single conduit connecti-ble at one end to a source of pressure fluid and at its other end to said fluid operator means of said latch means, and

a conduit in fluid communication with said single conduit inter-mediate the ends thereof and connected to said annular chamber means, the above conduits and fluid connections being arranged in a manner whereby the fluid operator means of said latch means and said resilient annular seal member are simultaneously actuated upon pressurizing the single conduit.

2. The apparatus of claim 1 wherein the inner wall of said body member forming the axial passage therethrough has an annular recess for containing said annular seal member.

References Cited by the Examiner UNITED STATES PATENTS Re.18,948 9/33 McNefE 166-88 X 2,212,036 8/40 Otis 285-140 X 2,264,600 12/41 Webb.

2,401,119 5/46 Taylor 285-140 X 2,598,133 5/52 Roesch 74-537 X 2,656,025 10/53 Martin 75529 X 2,873,822 2/59 Sloan 74-527 X 2,903,907 9/59 Powell 74-529 X 3,117,466 1/64 Hinsey 74-529 X 3,147,922 9/64 Haeber 285-18 FOREIGN PATENTS 955,180 6/49 France.

CARL W. TOMLIN, Primary Examiner. 

1. A WELLHEAD CONNECTOR ASSEMBLY COMPRISING A BODY MEMBER HAVING A PASSAGE EXTENDING AXIALLY THERETHROUGH, SAID BODY MEMBER BEING POSITIONABLE IN TELESCOPIC RELATION WITH VERTICAL WALL MEANS OF A LONGITUDINALLY PROJECTING WELL MEMBER HAVING AN AXIAL PASSAGE THERETHROUGH FORMING AN UNIMPEDED THROUGHBORE PASSING THROUGH SAID BODY MEMBER AND SAID WELL MEMBER, COOPERATING CONNECTOR MEANS CARRIED BY THE ADJACENT WALLS OF SAID BODY MEMBER AND SAID WELL MEMBER, ONE PORTION OF SAID CONNECTOR MEANS COMPRISING SHOULDER MEANS FORMED BY A RECESSED AREA IN THE OUTER WALL OF SAID WEL MEMBER, THE OTHER PORTION OF SAID CONNECTOR MEANS COMPRISING SHOULDER-ENGAGING LATCH MEANS CARRIED BY SAID BODY MEMBER IN THE ADJACENT WALL THEREOF IN A POSITION FOR REGISTERING WITH SAID SHOULDER MEANS, SAID LATCH MEANS BEING SUBSTANTIALLY LATERALLY MOVABLE INTO AND OUT OF ENGAGING RELATION WITH SAID SHOULDER MEANS, COMPRESSION SPRING MEANS CARRIED BY SAID BODY MEMBER IN OPERATIVE ENGAGEMENT WITH SAID LATCH MEANS FOR NORMALLY URGING SAID LATCH MEANS INWARDLY AT ALL TIMES INTO ENGAGEMENT WITH SAID SHOULDER MEANS, FLUID OPERATOR MEANS FOR SAID LATCH MEANS CARRIED BY SAID BODY MEMBER AND OPERATIVELY CONNECTED TO SAID LATCH MEANS FOR URGING SAID LATCH MEANS TO A RETRACTED POSITION OUT OT ENGAGEMENT WITH SAID SHOULDER MEANS. LATCH LOCKING MEANS CARRIED BY SAID BODY MEMBER ADAPTED TO LOCK SAID LATCH MEANS IN A RETRACTED POSITION, A RESILIENT ANNULAR SEAL MEMBER ON THE INNER WALL OF SAID BODY MEMBER FORMED BY THE AXIAL PASSAGE THERETHROUGH, SAID SEAL MEMBER BEING RADIALLY INWARDLY CONTRACTIBLE ABOUT A WELL MEMBER WHEN IT IS POSITIONED IN SAID AXIAL PASSAGE, CHAMBER MEANS FORMED IN SAID BODY MEMBER AROUND THE OUTSIDE OF SAID ANNULAR SEAL MEMBER, SAID CHAMBER MEANS ADAPTED TO BE CONNECTED TO A SOURCE OF FLUID PRESSURE, WEIGHT-SUPPORTING SHOULDER MEANS FORMED ON THE INNER WALL FORMING THE PASSAGE THROUGH SAID BODY MEMBER FOR SEATING ON SAID WELL MEMBER WHEN IN ENGAGEMENT THEREWITH, AND A SINGLE CONDUIT CONNECTIBLE AT ONE END TO A SOURCE OF PRESSURE FLUID AND AT ITS OTHER END TO SAID FLUID OPERATOR MEANS ON SAID LATCH MEANS, AND A CONDUIT IN FLUID COMMUNICATION WITH SAID SINGLE CONDUIT INTERMEDIATE THE ENDS THEREOF AND CONNECTED TO SAID ANNULAR CHAMBER MEANS, THE ABOVE CONDUITS AND FLUID CONNECTIONS BEING ARRANGED IN A MANNER WHEREBY THE FLUID OPERATOR MEANS TO SAID LATCH MEANS AND SAID RESILIENT ANNULAR SEAL MEMBER ARE SIMULTANEOUSLY ACTUATED UPON PRESSURIZING THE SINGLE CONDUIT. 